News of the World Accused of Hacking Phone of Murdered Girl, Milly Dowling

A story that has gripped Britain for a decade has now taken a bizarre twist. London's News of the World, a weekly tabloid focused on celebrity and crime scoops, is accused of hacking into the voicemail of a missing teenage girl in pursuit of exclusive stories.

The case involves 13-year-old Milly Dowler, who disappeared in March 2002. Her remains were found southwest of London six months later.

Just two weeks ago, a convicted double murderer was found guilty of killing Dowler and the case was closed. But it is now back in the headlines with revelations that reporters not only listened to the teenager's voicemail, but deleted voicemail messages -- leading her parents to believe she was still alive and potentially obstructing the police investigation into her disappearance.

Rebekah Brooks, Chief Executive of News International, the company that owns the paper, emailed her staff Tuesday about the allegation, saying she was "sickened that these events are alleged to have happened." She said, "If the accusations are true, the devastating effect on Milly Dowler's family is unforgivable." Brooks, who was editor of the tabloid at the time, is now media mogul Rupert Murdoch's top lieutenant. There is a rising chorus of calls for her resignation, with critics saying she either knew about the hacking and did nothing, or simply did not know what her paper was doing in its aggressive pursuit of a story.

"It is distress heaped upon tragedy to learn that the News of the World had no humanity at such a terrible time," said Mark Lewis, lawyer for the Dowler family. "The fact that they were prepared to act in such a heinous way that could have jeopardized the police investigation and give them false hope is despicable."

Prime Minister David Cameron said Tuesday he was shocked and called for a thorough police inquiry into the accusations.

"If they are true, this is a truly dreadful act and a truly dreadful situation," Cameron said.

Ford UK, the British division of the automotive giant, said it would stop advertising in News of the World because of the hacking. Virgin Media and the giant grocery chain Tesco said they were considering pulling their ads as well.

This isn't the first time News of the World has been caught in a phone-hacking scandal. A private investigator and an editor were jailed in 2007 after it was revealed they had tapped the phones of royal household staff. Five more people have been arrested since a fresh police investigation began in January.

"What you're looking at here is with [tabloid] papers is a furiously competitive world where the paper circulation was falling," George Brock, professor and head of journalism at City University of London, told ABC News.